1. Field of the Invention
The present invention relates to a combination weighing apparatus with an improved flow of articles.
2. Description of the Prior Art
Such a combination weighing apparatus as shown in FIG. 2 has hitherto been well known in the art. Referring to FIG. 2, articles M falling by gravity onto a central portion of a dispensing feeder 2 are supplied into a plurality of weighing hoppers 6i through a corresponding number of supply troughs 3i by way of associated pool hoppers 4i. The weighing hoppers 6i are each provided with a weight detector 7i for detecting the weight of the articles M supplied into the corresponding weighing hopper 6i. When a combination of weights of the articles M detected respectively by the weight detectors 7i attains a target weight or an approximate target weight close to the target weight, the articles M contained in some of the weighing hoppers 6i that have been selected in the combination are discharged from those selected weighing hoppers 6i collectively onto a collecting and discharging chute 9 and are then discharged downwards towards a next processing station.
Referring to FIG. 1, quantities of articles M successively discharged from a combination weighing apparatus 1 and then falling onto a chute 203 are successively packaged by a bagging and packaging machine 200. While the articles M falling from above are filled into a tubular film F, the bagging and packaging machine 200 fuses (seals) and then cuts an upper end F1 of the film F positioned above the articles M, to thereby continuously package products M1. The products M1 thus packaged are transported to a weight checker 300 which checks whether or not the weight of the articles M fall within a predetermined range.
In the above-stated system, if the articles M are bulky such as potato chips, they may interfere with one another at a passage-tapered portion A1 of a funnel-like chute 203, the flow of the articles M become slower or they sometimes form a bridge and completely clog. Besides, since this system operates at high speed, large amounts of articles M accumulate in a short period of time if the articles M begin clogging. It takes a lot of time and labor to remove the large amounts of accumulated articles M and to restart the system, with the result that system operativity disadvantageously deteriorates.
It is, therefore, an object of the present invention to promptly detect abnormality in the flow of articles and to maintain the high operativity and productivity (yield) of a combination weighing apparatus.
To this end, a combination weighing apparatus according to one aspect of the present invention is of a design wherein a combination of some of weighing hoppers accommodating therein articles that have been supplied thereto, which combination results in a combination calculated value of measured weights of the articles contained in some of the weighing hoppers forming the combination, falling within a predetermined combination tolerance, is selected and the articles in the selected weighing hoppers are subsequently discharged therefrom. This combination weighing apparatus is featured in that a timing for discharging the articles from the hopper is adapted to be automatically changed for at least one of hoppers in accordance with a condition of a flow of the articles on a falling route downstream of the combination weighing apparatus so that virtually no clogging of the articles occurs.
According to one aspect of the present invention, if there is a likelihood of the articles being clogged, such likelihood is determined, and then a simultaneous discharge is changed to a staggered discharge or the time differences among discharge timings of the hoppers is changed, thereby turning a condition in which the contents are likely to be clogged into a condition in which virtually no clogging of the contents occurs. In this way, the discharge timing for discharging the articles from the hopper is adapted to be automatically changed for at least one of hoppers in accordance with the condition of the flow of articles. Thus, it is possible to prevent the articles from completely clogging on the downstream route. Accordingly, it is possible to maintain the operativity of the apparatus high.
Furthermore, if discharge timing is stored for each product type, it is possible to maintain high operativity for each product.
Moreover, if discharge timing pattern is selected from among preset, stored patterns, it is possible to prevent the processing capability from being lower than the necessary processing capability.
A combination weighing apparatus according to another aspect of the present invention is of a design wherein a combination of some of weighing hoppers accommodating therein articles that have been supplied thereto, which combination results in a combination calculated value of measured weights of the articles contained in some of the weighing hoppers forming the combination, falling within a predetermined combination tolerance, is selected and the articles in the selected weighing hoppers are subsequently discharged therefrom. This combination weighing apparatus is featured in that a timing for discharging the articles from the hopper is adapted to be automatically changed for at least one of hoppers in accordance with a command from an apparatus different from the combination weighing apparatus so that virtually no clogging of the articles occurs.
According to another aspect of the present invention, if there is a likelihood of the articles being clogged, a simultaneous discharge is changed to a staggered discharge or the time differences among discharge timings of the hoppers is changed in response to a command from the difference apparatus, thereby turning a condition in which the contents are likely to be clogged into a condition in which virtually no clogging of the contents occurs.
In the present invention, the term xe2x80x9ca flow of articlesxe2x80x9d means a flow of articles from the time the articles are discharged from the hoppers of the weighing apparatus until they are filled into bags or the like.
The term xe2x80x9cautomatically changexe2x80x9d means change without keyboard manipulation by an operator. According to the present invention, therefore, discharge timing is changed in response to a change command from flow state detection means or the other apparatus.
Manners for making xe2x80x9cchange of discharge timingxe2x80x9d include respective manners in which the simultaneous discharge is changed to the staggered discharge, the time difference of staggered discharge is changed, and the number of hoppers or groups of hoppers having time differences is changed.